Going To Mogollon..., ...and points South Options

[Bill Harris]

It was already said that those structures seen on previous hazcam pics (well, in all sort of cameras and filters...) were delicate.

[attachment=3535:attachment] (138k)
But what about these ones? It looks like the smallest touch could broke them.

[attachment=3536:attachment] (138k)
PS: It's time to open a new thread, don't you think so?

Good idea. That topic was "tired" and had the cord showing.

Delicate, to be sure. One thing I've noticed is that the "ledge-forming" rocks are a layer and extend to the right and left of where we camped out. I wonder if that feature is related to the bluff at Mogollon Rim?

We need to check out the "mobile dust" at that site and see if there has been more movement during the stopover.
--Bill

[lyford]

Does it look like there was any piled deposition of dust to the right of where the rover wheels were parked for so long?

I realize there are several explanations for this, one of which that I am imagining it all, or it could just be an effect from driving disturbing the soil, and I don't even know if this would map to the right wind direction.

It might be evidence of some movement by wind, nonetheless.

EDIT - Original pic here.

[Bill Harris]

Ed, it may very well be that sand has piled up n the wiindward side of the right wheel. AFAIK, the prevailing wind direction seems to be coming more or less from the right, so it is possible. It could be that soil has been displaced, let's look at earlier and other images of that spot.

--Bill

[Tesheiner]

An article at Space.com:

http://www.space.com/missionlaunches/06012...nity_drive.html

"Opportunity will spend its time studying “Overgaard” along the rim of Erebus Crater for the next week or so before heading toward a new region of its Meridiani Planum landing site, mission managers said. "

[Guest_Sunspot_*]

..week or so?

[ilbasso]

They didn't say which week.

[CosmicRocker]

Well, that pretty much confirms that more MIs of the crossbedding are planned. I think we were warned that they were going to look over this exposure in detail. I am really anxious to get to Mogollon, but it would be pretty nice to get a big MI mosaic of that nifty stuff over Lower Overgaard.

[Bill Harris]

> I am really anxious to get to Mogollon, but it would be pretty nice to get a big MI mosaic...

Me too, this is a good opportunity to study x-bedding. We'll just have to sit here and fidget...

--Bill

[ElkGroveDan]

We'll just have to sit here and fidget...

This is what happens when you invite too many geologists to a party.

[Bill Harris]

Foo.



--Bill

[alan]

An article at Space.com:

http://www.space.com/missionlaunches/06012...nity_drive.html

"Opportunity will spend its time studying “Overgaard” along the rim of Erebus Crater for the next week or so before heading toward a new region of its Meridiani Planum landing site, mission managers said. "

Oppy leaving today?

717 p0650.01 0 0 0 0 0 0 navcam_10x1_az_90_1_bpp
717 p1201.03 0 0 0 0 0 0 front_haz_penultimate_1_bpp_crit16
717 p1214.05 0 0 0 0 0 0 front_haz_ultimate_4bpp_pri15
717 p1316.01 0 0 0 0 0 0 rear_haz_ultimate_4_bpp_pri41
717 p1938.07 0 0 0 0 0 0 Navcam_IDD_doc_crit19
717 p1939.04 0 0 0 0 0 0 navcam_idd_stow_workspace

[Shaka]

Oppy leaving today?

717 p0650.01 0  0  0  0  0  0    navcam_10x1_az_90_1_bpp
717 p1201.03 0  0  0  0  0  0    front_haz_penultimate_1_bpp_crit16
717 p1214.05 0  0  0  0  0  0    front_haz_ultimate_4bpp_pri15
717 p1316.01 0  0  0  0  0  0    rear_haz_ultimate_4_bpp_pri41
717 p1938.07 0  0  0  0  0  0    Navcam_IDD_doc_crit19
717 p1939.04 0  0  0  0  0  0    navcam_idd_stow_workspace

Alan,
The codes above are 'Greek' to me, but I would be shocked and bewildered if Oppy moved more than half a meter over the next week. After spending (wasting? ) a week MIing a slab without obvious festoon bedding, they have yet to map the slab that does have it (maybe). Anyway, they're still having trouble with Oppy's arm joints, so I fear we are going to be stuck here for a while yet.
Christmas is coming; the geese are getting...

[dot.dk]

Oppy leaving today?

From:
http://marsrovers.jpl.nasa.gov/mission/sta...tml#opportunity

Science team members next plan to adjust the rover's position slightly to conduct microscopic analysis of another target area, nicknamed "Upper Overgaard."

So no big movement yet...

[Shaka]

From:
http://marsrovers.jpl.nasa.gov/mission/sta...tml#opportunity
So no big movement yet... 

http://qt.exploratorium.edu/mars/opportuni...KWP1214R0M1.JPG
O.K. Oppy just stretched, boogied a little, and did a quick pan (deja vu ), just to keep in practice. There's life in the old girl yet!

[jvandriel]

The last images are down and here is the 360 degree panoramic view around Erebus.

Taken with the L1 pancam on Sol 712.

jvandriel

Attached thumbnail(s)

 

[slinted]

Since this is the thread for "...and points south", it seems as good a place as any for this little chuckle.

The homepage for the Mapping and GIS Laboratory at OSU (the routemap people) currently features a link to an article published in the Columbus Dispatch back on January 3rd. It includes some quotes from the Ron Li, the leader of the OSU mapping group, as well as 2 routemaps credited to the OSU group, showing the rovers progress up until December 22, 2005.

Imagine my surprise when I looked at the Opportunity routemap...not only did Opportunity already arrive at Victoria (which has shrunk to 200 feet wide, and is now apparantly renamed Erebus), but they have already driven partially around the rim

[Bill Harris]

I have long commented jokingly that the "route map" contractors seem to be clue-challenged because their route maps have been rather pitiful. I've also joked that they seem to be cloning the look-and-feel of the routmaps we produce here on UMSF since theirs have markedly improved in the last year.

Although I was joking, I don't think I was...

--Bill

[jamescanvin]

Since this is the thread for "...and points south", it seems as good a place as any for this little chuckle.

The homepage for the Mapping and GIS Laboratory at OSU (the routemap people) currently features a link to an article published in the Columbus Dispatch back on January 3rd.  It includes some quotes from the Ron Li, the leader of the OSU mapping group, as well as 2 routemaps credited to the OSU group, showing the rovers progress up until December 22, 2005.

Imagine my surprise when I looked at the Opportunity routemap...not only did Opportunity already arrive at Victoria (which has shrunk to 200 feet wide, and is now apparantly renamed Erebus), but they have already driven partially around the rim

And the Spirit one is no better. The insert is ok (I think) but the main map!

Attached thumbnail(s)

 

[SigurRosFan]

No Mogollon Rim close-up's??

http://athena.cornell.edu/news/mubss/

--- Once we've hit all the festoons on Upper Overgaard, then there are a couple of other nearby targets we've got our eyes on... one called Bellemont and another called Roosevelt. We'll go after one or both of those, and then it will be time to hit the road in a big way.

The drive south from here is going to be interesting. Victoria crater beckons, and we really want to lay down some serious mileage. ---

[Toma B]

No Mogollon Rim close-up's??

Don't be sad...just think about what would "Victoria Rim close ups" look like...

[Shaka]

No Mogollon Rim close-up's??

I sure there will be if it's safe to approach and there is evidence of a vertical section. A layer in the hand is worth two in Victoria. Getting to Victoria is still a dream. Erebus is reality!

[Guest_Sunspot_*]

According to the latest rover article at the Planetary Society website, they still plan to take what will probably be a quick look at the Mogollon Rim:

http://www.planetary.org/news/2006/0131_Ma...ate_Spirit.html

[Nirgal]

looks like they finally decided to switch the priority to driving in order to seriously try to reach Victoria Crater

quote from
http://www.planetary.org/news/2006/0131_Ma...ate_Spirit.html

“It is a sobering indicator that they won’t keep going and going forever. And that is an additional reason the team wants to try and get to Victoria Crater sooner rather than later.”

I'm very happy with this descision because I have always felt that the fact that the life time of the rovers is so limited should be a reason in favour of a more long-distance-oriented driving strategy rather than against it.

Now, after exceeding mission 'warranty' by about 10 times, the time has come for a more bold, exploratory strategy: Now we can really afford the risk of possibly losing some Sols of additional routine observations by trying to dedicate more of the remaining Sols for the only task of driving: Imagine just 40 Sols of driving-only at a prudent 30 meters/Sol would be about sufficient to cover the remaining kilometer or so to Victoria ! actually this is less time than that has been spent parked at the Olympia site alone.

Switching priorities to long-distance-driving means that maybe they will even decide to completely stow the IDD again for the duration of the Victoria Trek... unstowing it only at Victoria or if really new discoveries pop up along the way...

Other promising quotes from the TPS article:

the things we were hoping we’d find at Mogollon we have found already at Olympia

A balance is necessary, but our hoped-for drive strategy is a pretty aggressive one, and the team is very anxious to head southward at a brisk pace now to get to Victoria Crater.

The current Festoon-Studies are the very necessary and important conclusion
of the intensive Erebus-studies but after that it's time for exploring new horizons again

[RNeuhaus]

The real interesting thing from Mogollon rim is the black or dark stones on its rim on the south side of Oppy's site. Maybe, they have already identified them as a rind?

Rodolfo

[tacitus]

looks like they finally decided to switch the priority to driving in order to seriously try to reach Victoria Crater

The current Festoon-Studies are the very necessary and important conclusion
of the intensive Erebus-studies but after that it's time for exploring new horizons again

Don't get too excited about the prospect of a rapid trip to Victoria just yet. As Squyres says, if they find something different and interesting at the Mogollon Rim they're not going to leave it behind unexamined.

My bet is it will be into March before they're done with Erebus completely.

[Nirgal]

Don't get too excited about the prospect of a rapid trip to Victoria just yet.  As Squyres says, if they find something different and interesting at the Mogollon Rim they're not going to leave it behind unexamined.

My bet is it will be into March before they're done with Erebus completely.

Yes D'Accord ! I, too think it's important to take all the time necessary to complete
the work at Erebus: may very well take another 4 weeks or so ...
What I'm looking forward too is that *after that* the Trip will go straight to Victoria
with prio one = driving and only stopping on really new discoveries

[Tesheiner]

What I'm looking forward too is that *after that* the Trip will go straight to Victoria
with prio one = driving and only stopping on really new discoveries

IMO they will follow an approach similar to Spirit's.

[Bill Harris]

I will agree. If it hadn't been for the IDD problem we would have already been at the Mogollon Rim, finishing up and heading to the next target.

I can't see them _not_ stopping at the dark-toned bluff area at Mogollon; this feature is not like one we've seen before.

--Bill

[Bill Harris]

Presented here is a 3x vertical exaggeration from jvandriel's Sol 733 Pancam stitch. The Mogollon Rim outcrop is on the right, Payson is on the left. Payson seems to be an interesting feature, note the small landslip on the left side.

One possible route may be a straight shot right of center to the dark float (outcrop).

Do you realize that we've been eyeballing this area since before Oppy hit the Erebus Highway? This site ought to be geo-nirvana...

--Bill

[Bob Shaw]

Anyone know what the strategy is for Opportunity regarding winter, and how that translates into travel plans?

Bob Shaw

[Tesheiner]

Anyone know what the strategy is for Opportunity regarding winter, and how that translates into travel plans?

Bob Shaw

Good question (Doug, take note of that for the next interview).

On this flat terrain the option of a "hill's north slope" is ... not an option, and I guess the winter will hit Oppy on the middle of the travel to Victoria.
How this translates on travel plans: maybe shorter drives due to less available energy, and imo more important, very careful driving when traversing by the dunes/ripples. Just think of what could happen after an aborted drive with a bad tilt?

[Burmese]

http://www.newscientistspace.com/article.ns?id=dn8730

"Jacob Matijevic, the rover mission team's chief of engineering, also at JPL, said if possible, the team would like Opportunity to winter in Victoria Crater, a large impact crater 2500 to 3000 metres away. "That would have the same benefit as we saw in our investigations of Endurance Crater," Matijevic says.

The journey to Victoria Crater is likely to take at least three months, he adds."

[helvick]

Good question (Doug, take note of that for the next interview).

On this flat terrain the option of a "hill's north slope" is ... not an option, and I guess the winter will hit Oppy on the middle of the travel to Victoria.
How this translates on travel plans: maybe shorter drives due to less available energy, and imo more important, very careful driving when traversing by the dunes/ripples. Just think of what could happen after an aborted drive with a bad tilt?

Oppy has a slight benefit in terms of location at mid SH winter since it is so close to the equator (1.95deg S) vs Spirit at 14.57deg S. In practical terms this gives Oppy approximately 15% more insolation at mid winter. It also means that Oppy will have a slightly easier time finding optimal slopes from an insolation perspective, and finally the penalty for ending up in an unfavourable position is less than it will be for Spirit.

The precise amount of dust on the panels could still cause a major problem for either rover but all other things being equal Oppy has an easier environmental situation in SH winter time.

[Bill Harris]

Also since this site a only a couple of degrees South of the equator there is not much difference between the mid-summer and mid-winter altitude of the Sun (62 and 68 degrees, respectively) so it might seem that a north-facing slope isn't critical. But given that these angles represent a loss of 47% and 37% based on ther cosine function, it might require some north-facing slopes to increase the solar incidence on the solar panels.

The big problem is the orbital eccentricity. Mars is some 19% farther from the Sun in the Martian Southern Winter (which we are approaching) so the sunlight will be less intense by xx% so some time on a north-facing slope may be needed to top up the batteries.

--Bill

[djellison]

Power 19% further out will be 41% lower, I think

Doug

[Phil Stooke]

Burmese quoted a story from New Scientist,

"the team would like Opportunity to winter in Victoria Crater"

Oh come on! There's no way. I'd like to see it, certainly, but it can't possibly get there until spring.

Phil

[Tesheiner]

Not only that, but the rover would have to make the whole way around the crater to it's southern size (northern looking wall) AND find a path into the crater.

[Toma B]

Not only that, but the rover would have to make the whole way around the crater to it's southern size (northern looking wall) AND find a path into the crater.

Oh, but we aren't going to Victoria just yet as Jim Bell says...
There are some more places around that they want to see, and maybe then they will decide that there are some more places nearby, after that there will be some more IDD to be done here, after that there will be some things that we have never seen before...
Opportunity will never reach Victoria Crater at this pace...PLEASE make up your mind and start DRIVING!!!

[helvick]

Power 19% further out will be 41% lower, I think

The local microclimate and dust deposition\cleaning patterns are causing major differences at the moment it seems.New Scientist MER update.

Jones says in order to be productive during a sol, the rovers need at least 400 watt-hours. That amount of power allows an hour-long drive, a couple hours of robotic arm work or remote sensing and a daily data uplink to the Mars Odyssey spacecraft. To simply stay alive, they need about 280 watt-hours.

Spirit is currently operating with about 450 watt-hours per sol, but the available power has dropped by about 100 watt-hours over the past 50 sols, Jones says.
.....
The coming winter is less pressing for Opportunity, which is closer to the equator and is still operating with about 600 watt-hours of power each sol.

Time for me to go off and properly calculate some power curves for the onset of winter but my quick calculations tell me that Oppy will stay above about 330 whr throughout winter and has at least three months ahead when she should be able to manage an hour or more driving per sol. Spirit is losing between 10 and 15 whr per week at the moment so she really has to get to McCool hill within about 40 Sols or she risks getting stranded in a less than ideal spot unable to move.

[Nirgal]

Time for me to go off and properly calculate some power curves for the onset of winter

Thanks helvick !
I've been already anxiously waiting for your detailed update ... major concern was for Oppy not reaching the slopes of Victoria in time (whereas Spirit will have no problems to reach it's winter parking position)
... I thought it must come close to the 300 Watts "deadline" even for Oppy .... so the cited 330 W minimum for Oppy is encouraging ...
And, unfortunately, as for further cleaning events, as nice as they are, they are not something we can count on ...

[Marcel]

B)-->

Opportunity will never reach Victoria Crater at this pace...PLEASE make up your mind and start DRIVING!!!

[/quote]

I can understand the frustration. I'd love to see the place as well: the possibility to reach it is there, and this will diminish every day that long drives south are postponed and mechanics and electronics are aging.

But (and it's said before often): This mission is not about pretty pictures, it's about science. About understanding what we see. Try to reconstruct what happened on this part of the surface. Relate morphology with rock/soil composition (while the cobalt source still radiates within workable levels, before it's out of operation), look for geologic context. And: do it as thoroughly as possible. This, combined with the knowledge that the quality of the scientific results is highly dependent on the quantity (that is: statistically reliable) AND te quality of the data (that is: complete, without forgetting to record just about everything that's within the capability of the instruments). And this costs time. A lot of it. And this is why we're not in Victoria (yet). It's a balance between continuing the trek across the line southward and feeding hunger for new terrain, and relating it to the knowledge that returning to a spot to fill a gap in the data is probably not going to be an option.

In other words: it's choosing between knowing some things for sure (like the prime target: pinning down water related processes), than a lot of things superficially.

[Nirgal]

But (and it's said before often): This mission is not about pretty pictures, it's about science.

My feeling is that Victoria will offer both: "pretty pictures" *and* the most valuable science at the same time
just as it has been the case with the other long distance treks to Endurance, Columbia Hill Summit
and now Home Plate. Imagine we could be still turning every pebble at "Adirondack" but so far, each time we did take the "risk" of driving longer distances to new horizons, the reward has been a whole new chapter of discoveries there
Apart from accuracy and thouroughness It has always been also the Couriosity and the explorative spirit of trying new things and taking risks that have been the drving force behind science

[helvick]

Victoria is apparently somewhere between 2500 and 3000m away depending on the route taken.

To see how realistic a target it is I'm making some assumptions:
1. Driving consumes approximately 100watts between the drive motors and navigation processing\imaging.
2. 0.5 cm/sec is a realistic speed for driving aggresively but with some care (so as to avoid another Purgatory).
3. Dust accumulation will cause additional power loss at a rate of 0.18% per Sol (this should be a worst case situation).
4. Oppy doesn't get stuck.
5. We start driving soon.

Opportunity should have enough power available over the next 94 sols (when power will drop just below 400 whr) to drive about 3300m.

To achieve that she would have to start soon and initially average around 50-60m per Sol. By the time she reaches Victoria she would be driving for about 18m per Sol.

I haven't factored in things like restricted Sols but there is a 10-30% margin in the above numbers depending on route and my calculations target reaching Victoria when power is still approx 400whr per Sol so she still has enough juice to do some real work\find a nice sunny ledge to park on for winter.

[Marcel]

Imagine we could be still turning every pebble at "Adirondack"

Which would make no sense, because there was nothing but volcanic rock there. Oppy however, is in a treamendous complex and interesting spot at the moment. This combined with the problems with her arm, and all the microscopic work makes that it's been a while around here. I must admit however, that continuing to another spot is about time.

[djellison]

Not only that, but the rover would have to make the whole way around the crater to it's southern size (northern looking wall) AND find a path into the crater.

OR - outside the crater on the northern slope that approaches the rim ?

Remember the southern slope they had driving around the southern edge of endurance making Oppy very power-low (in SS's book)

Doug

[Marz]

Victoria is apparently somewhere between 2500 and 3000m away depending on the route taken.
.... To achieve that she would have to start soon and initially average around 50-60m per Sol. By the time she reaches Victoria she would be driving for about 18m per Sol.

Yikes! 50m/Sol is pretty aggressive around Erebus. Maybe if the dunes flatten out a bit. The manuevering up to Erebus was pretty darn slow, with few drives being more than 20m.

Well, as Daffy Duck would sing, "you never know where you're goin' till ya get there!"

[Marslauncher]

So didnt I read that we should have had a drive? hope the pictures come down soon!

I am itching to see new pictures!

John Cooke

[Shaka]

So didnt I read that we should have had a drive? hope the pictures come down soon!

I am itching to see new pictures!

John Cooke

There's an epidemic of that kind of pruritis, John. But the drive was aborted due to continuing arm stalls.

Sol 734: The plan for this sol was to stow the arm, drive about 36 meters (118 feet) to an area known as "Zane Grey," and unstow the arm. The arm stalled just before it reached the ready position (before stowing), and the drive did not occur.

Latest JPL update. Can anybody calculate where this Zane Grey is, 36m from our present position? Is it the black rubble pile or is it the rim proper?

[bergadder]

--><div class='quotetop'>QUOTE(Toma B @ Feb 16 2006, 07:59 PM) </div><div class='quotemain'><!--quotec-->
Opportunity will never reach Victoria Crater at this pace...PLEASE make up your mind and start DRIVING!!!

I can understand the frustration. I'd love to see the place as well: the possibility to reach it is there, and this will diminish every day that long drives south are postponed and mechanics and electronics are aging.

But (and it's said before often): This mission is not about pretty pictures, it's about science.

We also need to remember that there is another Science that must be covered, and that is the science of protecting the JPL budget from manned spaceflight. At this time when money is been diverted away from science, its time of a show for the public, senate and any oversite group on that budget. And I think a great show would be Victoria Crater. Risk/reward tough call...

[Marslauncher]

I fully support science days and investigation, I am just as eager as every one else to move on however , is there any consensus as to a work around for the arm stalls?

Thanks

John Cooke

[jamescanvin]

...the drive was aborted due to continuing arm stalls.

Latest JPL update. Can anybody calculate where this Zane Grey is, 36m from our present position? Is it the black rubble pile or is it the rim proper?

The update also says

Sol 735 (Feb. 16, 2006): The plan for this sol includes remote sensing and a short diagnostic activity for the arm.

Lets hope nothing more has gone wrong!

And just when we thought we were leaving...

James

[tacitus]

Are they still trying to stow the arm completely or in the new "safer" position above the solar panels for this longer drive?

[Tesheiner]

There's an epidemic of that kind of pruritis, John. But the drive was aborted due to continuing arm stalls.

Latest JPL update. Can anybody calculate where this Zane Grey is, 36m from our present position? Is it the black rubble pile or is it the rim proper?

Zane Grey can't be the rim 'cause it's about 90m+ away.
Imo, it's one of those two outcrops at the first leg on this old route proposal. The current pancam view is basically the same; Oppy has barely moved around the point she was on the end of november.


Original post: http://www.unmannedspaceflight.com/index.p...indpost&p=28324

[Tesheiner]

Are they still trying to stow the arm completely or in the new "safer" position above the solar panels for this longer drive?

The former.

[Guest_Sunspot_*]

The tech probs are really stacking up...Im begining to think that Opportunity will spend her last days around Erebus.

[djellison]

The tech probs are really stacking up...Im begining to think that Opportunity will spend her last days around Erebus.

Mobility wise, Opportunity is in fairly good health. Once they get that arm stowed, we'll be under way I'm sure.

Doug

[Bill Harris]

Imo, it's one of those two outcrops at the first leg on this old route proposal...

I would agree with your placement of the Zane Grey outcrop. I might suspect that it is the lefthand outcrop-- look at the 3x vert exagg I posted yesterday and the left route looks less sandy.

This puts us a couple of Sols from that "Nirvana outcrop"...

--Bill

[Tesheiner]

This puts us a couple of Sols from that "Nirvana outcrop"...

This puts us a couple of driving Sols from that "Nirvana outcrop"...

Let's hope tosol's troubleshooting is ok and we have Oppy on the move for sol 736... just hope; I won't make any bet.

[Bill Harris]

"We'll get there eventually..."

<sigh>

--Bill

[Bill Harris]

I picked up a "proper" L2 Pancam today at the JPL site which shows better detail than the R1 we looked at yesterday. Slightly tweaked and sharpened, I'm sharing cropped views of the exposure at Mogollon with no vertical exaggeration and with 3x vertical exaggeration.

--Bill

[djellison]

Looks like a little slice of a baby Burns Cliff in places.

Doug

[Marz]

I was just surfing the sol 734 images and noticed one of them shows a dune that's rather dark:

http://marsrovers.jpl.nasa.gov/gallery/all...NTP2446R2M1.JPG

Since it's closer than the cliffs, could this be the target Zane Grey?

[Bill Harris]

The dark-toned dune is Payson. Zane Grey is the light-toned patch at the right midground on the image you referenced.

--Bill

[Marcel]

Mobility wise, Opportunity is in fairly good health. Once they get that arm stowed, we'll be under way I'm sure.

Doug

I don't understand why they completely stow the arm as soon as a long drive needs to be done. Why is this so important ? Do they really think something will break while the arm is in "half stowed" position (over the solar panel) ? They drive 5 mm's a second. It's not " bumping", it is like a snail creeping across the terrain ! I've been asking this to myself for a long time. Maybe i oversee something, but the risk of another winding breaking in the faulty joint (thereby completely disabling the possibility to UNstow the IDD for the rest of the mission) looks much higher to me, than the chance of breaking something because of driving in the alternative (half stowed) position. There are two primairy windings in these motors aren't there ? There's only one left. And forcing a higher current trough it at this stage (while materials are getting old) doesn't make sense to me. I'm puzzled. It has been unstowed AFTER a pretty bad situation of stalls and erronous behaviour. LEAVE IT THERE ! Or maybe i'm not informed well enough....

[djellison]

I don't understand why they completely stow the arm as soon as a long drive needs to be done. Why is this so important ? Do they really think something will break while the arm is in "half stowed" position (over the solar panel) ? They drive 5 mm's a second. It's not " bumping", it is like a snail creeping across the terrain !

If you hunt back in the movie archive at the JPL site, you'll see some rover driving videos - ditto the NOVA programs - and given that there's essentially a tiny tiny bit of suspension within the wheels but nothing else - it's quite a rough ride even over the fairly flat rocks and terrain we have here.

Given that suprisingly bumpy ride, the mass of the instruments on the IDD, and the leverage they'd have on the joints and motors when in the 'hover' position, there is a real risk of damage to IDD joints, motors, even the front of that array and the nearest instrument.

Hence the high-park for short drives, and the proper drive for longer driving campaigns.

Doug

[mars_armer]

The simulations that have been run with an unstowed arm involve a single wheel sideslipping off a rock and free-falling some distance. This scenario isn't too unlikely, even when driving slowly. And Doug is right, the "suspension" is very hard so the rover and arm get a good jolt when that happens. The worst thing is that the unstowed arm gets thrown sideways as well.

The arm design was highly optimized to stay within a very tight mass budget (~4 kg for the arm, and the instrument package is ~2 kg). Because of those constraints, the arm was never designed to take these kinds of loads. A single-wheel drop off a 3-centimeter rock edge gets pretty close to the documented capability of the arm when in the hover-stow position.

Something else to remember is that the joint 1 winding failure was almost certainly caused by thermal cycling (remember the stuck heater on Oppy's shoulder). So the expectation is that the joint will fail completely from a thermal cycle, not from operation. So for longer drives, where they can't see the terrain in advance, it is considered fairly safe to stow the arm before driving and then unstow after the drive. (Of course, there's still the occasional stall because it's tricky operating the motor with a broken winding.)

Hope this helps explain the logic behind what they are doing.

[jamescanvin]

The simulations that have been run with an unstowed arm involve a single wheel sideslipping off a rock and free-falling some distance. This scenario isn't too unlikely, even when driving slowly. And Doug is right, the "suspension" is very hard so the rover and arm get a good jolt when that happens. The worst thing is that the unstowed arm gets thrown sideways as well.

The arm design was highly optimized to stay within a very tight mass budget (~4 kg for the arm, and the instrument package is ~2 kg). Because of those constraints, the arm was never designed to take these kinds of loads. A single-wheel drop off a 3-centimeter rock edge gets pretty close to the documented capability of the arm when in the hover-stow position.

Something else to remember is that the joint 1 winding failure was almost certainly caused by thermal cycling (remember the stuck heater on Oppy's shoulder). So the expectation is that the joint will fail completely from a thermal cycle, not from operation. So for longer drives, where they can't see the terrain in advance, it is considered fairly safe to stow the arm before driving and then unstow after the drive. (Of course, there's still the occasional stall because it's tricky operating the motor with a broken winding.)

Hope this helps explain the logic behind what they are doing.

Perfect!

I am surprised how tricky it seems to be operating the broken motor, I would have expected it to be very predictable. But then what do i know, I'm a scientist not an engineer!

James

[Jeff7]

Perfect!

I am surprised how tricky it seems to be operating the broken motor, I would have expected it to be very predictable. But then what do i know, I'm a scientist not an engineer!

James

They said that they're running the arm by giving it more current. I'd imagine that feeding it too much current all the time would just burn out something, or at the very least, heat it up.

[tacitus]

I suppose one thing the stowing problems might mean is that the rover team may be less willing to unstow the arm and use it on passing terrain unless there is something really interesting to look at, meaning fewer stops on the way to Victoria Crater. That should please some people!

[mars_armer]

Actually, the present strategy means the arm is never permanently stowed. It only gets stowed during a long drive, then immediately unstowed to the ready position at the end of the drive. This is to ensure that the arm is unstowed if/when the joint 1 motor finally gives out.

The joint 1 motor (with the broken winding) is difficult to operate because its electrical properties fluctuate as the motor goes through a turn, as the broken wire commutates. This only causes trouble when the motor is starting or stopping, as it has to overcome the magnetic detents.

[Cugel]

Actually, the present strategy means the arm is never permanently stowed. It only gets stowed during a long drive, then immediately unstowed to the ready position at the end of the drive. This is to ensure that the arm is unstowed if/when the joint 1 motor finally gives out.

The joint 1 motor (with the broken winding) is difficult to operate because its electrical properties fluctuate as the motor goes through a turn, as the broken wire commutates. This only causes trouble when the motor is starting or stopping, as it has to overcome the magnetic detents.

Question: does this mean that when the joint motor does fail and the arm can not be stowed anymore, there will be no more long drives for Opportunity? And can we conclude from this that the team has decided that a rover without IDD has less scientific value than a relatively static platform with IDD?

[helvick]

Yikes! 50m/Sol is pretty aggressive around Erebus. Maybe if the dunes flatten out a bit. The manuevering up to Erebus was pretty darn slow, with few drives being more than 20m.

I've taken the time to properly rework the current power generating capability of both rovers. You can see the charts in this post on the Oppy vs Spirit power consumption thread .

Opportunity really is in a very healthy power state right now and will continue to generate more than 457 whr/sol throughout the SH winter season. The chance of anything changing that before the onset of Spring begins to add dust back into the atmosphere is very low. Tau should begin to rise again around Sol 1000/November 16 2006 but by then insolation will be rising fast. The risk of a killer storm after that remains at around 20% but that's a long way off at the moment.

She has no particular need to rush to a wintering spot and should in general be able to drive for more than 90 minutes per Sol. That means that I'm pretty confident that she'll reach Victoria even if she is limited to 20m/sol provided nothing significant breaks. Given that I think it's fair to say the current caution with the arm is very prudent.

Spirit on the other hand absolutely has to get to a favourable wintering spot very soon or she'll find herself unable to move.

[RNeuhaus]

Actually, the present strategy means the arm is never permanently stowed. It only gets stowed during a long drive, then immediately unstowed to the ready position at the end of the drive. This is to ensure that the arm is unstowed if/when the joint 1 motor finally gives out.

The joint 1 motor (with the broken winding) is difficult to operate because its electrical properties fluctuate as the motor goes through a turn, as the broken wire commutates. This only causes trouble when the motor is starting or stopping, as it has to overcome the magnetic detents.

One solution for keeping the unstowed the arm with minimal harm due to the surface vibration caused by the unlevel surface and/or passing over any stones is that Oppy must look another ways that is sand. The sand surface are very, very smooth, it is very very nice to drive over that and it is almost alike to surf among sea waves. That is try to travel close to the ripples of sand if the center have outcrops.

Rodolfo

[hugh]

can we conclude from this that the team has decided that a rover without IDD has less scientific value than a relatively static platform with IDD?

I'm wondering about this too. I certainly hope not. Even without the IDD arm the rover still has all the cameras except the MI, plus the mini-TES. The RAT is at or near the end of its useful life. The whole point of having a rover is to have mobility, so to be mobile should have priority, and the sooner the better.

[djellison]

The sand surface are very, very smooth,

And very 'Purgatory' They were hunting for rock to drive on around Erebus ( remember the Erebus highway? ) - better to park the IDD, have a slightly rougher ride, but stick on the rock.

Doug

[Holder of the Tw...]

Probably get just a little bit more science done too, even if it's only photographing exposed bedrock close up while in transit. And I'm all for "transit" at this point. The more, the better.

[Nirgal]

Question: does this mean that when the joint motor does fail and the arm can not be stowed anymore, there will be no more long drives for Opportunity? And can we conclude from this that the team has decided that a rover without IDD has less scientific value than a relatively static platform with IDD?

I'm wondering about this too. I certainly hope not. Even without the IDD arm the rover still has all the cameras except the MI, plus the mini-TES. The RAT is at or near the end of its useful life. The whole point of having a rover is to have mobility, so to be mobile should have priority, and the sooner the better.

I agree completely !
when one thinks about it: one single Rover that is capable of doing medium to long distance drives is kind of equivalent to *multiple* static space probes landed on different places of the planet
so in essence 1 Rover = several "Viking-type" static platforms
with this huge, inherent advantage of a Rover (compared to all former static probes) in mind I have been
asking myself why with the MER mission the "static operations" always seemed to have gained clear priority
over the roving (mobile) operations ... and with the new unstowed-drive policy, again, the priority seems clear: take the risk of jeopardazing the whole (mobility of the)rover in favour of the IDD ..
If the priority was on Roving/Mobility instead, the strategy could have been to keep the arm stowed completely for the safest driving possible and make use of the arm much more "parsimoniously" to save it for less frequent, (but potentially more interesting) further targets along the way ...

[Guest_Sunspot_*]

We're a couple of days away from spending 3 months in the same location.

[alan]

Question: does this mean that when the joint motor does fail and the arm can not be stowed anymore, there will be no more long drives for Opportunity? And can we conclude from this that the team has decided that a rover without IDD has less scientific value than a relatively static platform with IDD?
I agree completely !
when one thinks about it: one single Rover that is capable of doing medium to long distance drives is kind of equivalent to *multiple* static space probes landed on different places of the planet
so in essence 1 Rover = several "Viking-type" static platforms
with this huge, inherent advantage of a Rover (compared to all former static probes) in mind I have been
asking myself why with the MER mission the "static operations" always seemed to have gained clear priority
over the roving (mobile) operations ... and with the new unstowed-drive policy, again, the priority seems clear: take the risk of jeopardazing the whole (mobility of the)rover in favour of the IDD ..
If the priority was on Roving/Mobility instead, the strategy could have been to keep the arm stowed completely for the safest driving possible and make use of the arm much more "parsimoniously" to save it for less frequent, (but potentially more interesting) further targets along the way ...

I suppose for some on the science team a rover without the IDD is just a Mars Tourism Rover.

[tacitus]

I suppose for some on the science team a rover without the IDD is just a Mars Tourism Rover.

Well the main objective of the mission is to find evidence of water on Mars. Without the IDD that mission is severely hampered. It's a judgement call they are continually having to make but it seems to me that for now they are still putting the future use of the IDD ahead of zooming off to Victoria.

It's a tough spot to be in, but I suspect they will continue to baby the arm until they're done with Erebus. With a significant vertical rock face within easy reach, they want to make sure they still have the IDD available to examine it. After that, perhaps then they will make Victoria number one priority.

[Bill Harris]

It would be nice to have the IDD instruments, but with reconnaisance geology the primary thing one needs is boots and eyes (ie, a mobile Rover with functional Pancams); the handlens and scratchplate are useful but not essential. Oppy needs to stow the IDD and get to the next outcop...

--Bill

[ElkGroveDan]

It would be nice to have the IDD instruments, but with reconnaisance geology the primary thing one needs is boots and eyes (ie, a mobile Rover with functional Pancams); the handlens and scratchplate are useful but not essential. Oppy needs to stow the IDD and get to the next outcop...

--Bill

I agree with you Bill, but I should point out that without the IDD our science in Endurance would have consisted of a lot of pictures of pretty stripes along the cliffs. The rules of superposition are kind of useless on an alien world without a means to put it all in context. (Wouldn't it be nice if a future mission had an isotopic absolute dating instrument?) Although now that we have some details on Endurance's layers, I'm guessing that we will be able to visually correlate those same layers in Victoria. But of course, the hope is we will find some deeper, older layers we haven't looked at yet. If those layers are chock full of rotini beastie fossils, I'll sure want to have the MI working

I would say though that if the Pancam was the last functioning device on Oppy, it sure would be poetic fate for Steve Squyers.

[neb]

It would be nice to have the IDD instruments, but with reconnaisance geology the primary thing one needs is boots and eyes (ie, a mobile Rover with functional Pancams); the handlens and scratchplate are useful but not essential. Oppy needs to stow the IDD and get to the next outcop...

--Bill

Bill: I am in total agreement. They need to find a way to stow it and get moving again. I doubt we will find anything so totally different that we can't visually understand it. Ben

[Shaka]

Bill: I am in total agreement. They need to find a way to stow it and get moving again. I doubt we will find anything so totally different that we can't visually understand it. Ben

Ahhhh. I think I detect a gauntlet hurled to the dust! Visual vs. Analytical Geology. I love it!
I wonder how that debate might have fared in Gusev Crater - up until we arrived at Home Plate.
I wonder if Victoria will become the HP of Meridiani.

P.S. I hope we are all praying fervently for the recovery of Exploratorium. Where there's life there's hope.

[Toma B]

Question: does this mean that when the joint motor does fail and the arm can not be stowed anymore, there will be no more long drives for Opportunity? And can we conclude from this that the team has decided that a rover without IDD has less scientific value than a relatively static platform with IDD?

This question should be re-posted in "Jim Bell Q'n'a" topic...
I would like to hear answer to that...

[djellison]

If the IDD breaks, then do what can be done with where-ever it is, and then just start driving. If it breaks - so what ,it's expired anyway.

Doug

[hugh]

Well the main objective of the mission is to find evidence of water on Mars.

I suppose so, I just wonder if the fixation on water isn’t compromising other science objectives -like documenting as many types of surface feature as possible. There seems to be a bias operating in favour of studying subtle small-scale features (mostly water deposition evidence) and against studying large scale ones. Not trying to stir the pot but -is the purpose of this mission to look for support for the hypothesis that there was once standing water on Mars, or is it to characterize the surface of Mars as well as possible?

[djellison]

Not trying to stir the pot but -is the purpose of this mission to look for support for the hypothesis that there was once standing water on Mars, or is it to characterize the surface of Mars as well as possible?

Unquestionably the former.

Don't confuse scientific aspirations with engineering limitations. What the scientists would like to do is not always possible.

Doug

[jvandriel]

A panoramic view of Mogollon.

Taken on Sol 734 with the L2 pancam.

jvandriel

Attached thumbnail(s)

 

[Bill Harris]

They need to find a way to stow it and get moving again.

I can see the rationale for their current actions: the IDD may fail soon and become history, so they are trying to get most detailed information on the wonderful sedimentary structures while they can. But Jimminy Cricket, we've been at this site forever-and-a-day and we need to get to the next outcrop which might well be the Holy Grail of this region.

...is the purpose of this mission to look for support for the hypothesis that there was once standing water on Mars, or is it to characterize the surface of Mars as well as possible?

I'd say that they are (or should be) studying the Geology to find evidence of water.

--Bill

[JTN]

If the IDD breaks, then do what can be done with where-ever it is, and then just start driving. If it breaks - so what ,it's expired anyway.

Could IDD failure endanger the rover's other functions?
(e.g., if it snaps, it could foul the wheels or something)

[jabe]

Could IDD failure endanger the rover's other functions?
(e.g., if it snaps, it could foul the wheels or something)

I'm curious if the arm is snapped off and wires get "crossed" can they isolate the system so it isn't a constant power drain..
oh the worries we have for the rovers even though they should have died a LONG time ago..oops..hope I didn't jinx them..
jb

[djellison]

Could IDD failure endanger the rover's other functions?
(e.g., if it snaps, it could foul the wheels or something)

I guess it could - it's not the sort of situation I imagine they'd want to get in to, but there's nothing they could to to 'jetison' the IDD

Doug

[centsworth_II]

If the IDD breaks while extended they could drive backwards, dragging it along, taking care not to snag it on a rock.

[odave]

I hate contributing more negative waves to the discussion, but with all the recent hubbub about the NASA budget proposal, would funding for MER get cut if Oppy's IDD were to go out? I suppose a bean counter might think that with Oppy's capability impaired, it should get less resources, if not shut down?

No doubt everyone on the MER team would fight that kind of decision tooth and nail...

[ElkGroveDan]

I wonder if Victoria will become the HP of Meridiani.
[/i][/color]

Eagle Crater was the HP of Meridiani.

I'm curious if the arm is snapped off and wires get "crossed" can they isolate the system so it isn't a constant power drain..

If they have the ability to adjust the current to just one motor in the complex arm, then my guess is yes, they have the ability to isolate any circuit.

That said, a lot of things may happen, but short of a direct hit from a meteorite, I can't imagine anything in Opportunity's present environment that would cause the arm to "snap off". The present arm joint concerns center around functionality. This is a craft that was designed to mechanically withstand the g-forces of an interplanetary launch as well as the subtantial g's of the air bag bounce and roll. I am told there are MER's made of LEGO, but this isn't one of them.

[djellison]

I hate contributing more negative waves to the discussion, but with all the recent hubbub about the NASA budget proposal, would funding for MER get cut if Oppy's IDD were to go out? I suppose a bean counter might think that with Oppy's capability impaired, it should get less resources, if not shut down?

No doubt everyone on the MER team would fight that kind of decision tooth and nail...

I think as long as one rover is driving, then the money will still come, all be it in increasingly smaller ammounts. If we end up with a dead rover in terms of mobility, then there's only so long one can justify using it (a purgatory type of time probably- 3 months maybe ) - at that point you have to admit that there's not much more to do ( even JB said they were running out of things to do here at Erebus ) - and start a very restricted mode of operation - just occasional contacts etc.

Remember - they fund MER, not Spirit and Opportunity - it's one pot of cash, so as long as one is still doing good stuff, I think the money will still flow. The backlash and outrage if they do otherwise would 1) be audible in Washington from here in Leicester and 2) be huge in the US as well.

Doug

[Tesheiner]

Will we see "Oppy leaves Olympia (aka Purgatory II)" scene, take #3, tomorrow?

Just a guess/hope, no planning data yet at the tracking web.

[sranderson]

Unfortunately, we haven't found anything new with Opportunity in about a year. I can set up my geology shop at a random 2-foot exposure of layered rock near my house, study it ad nauseum for months and not really learn anything about the big picture of even the local area, let alone the whole planet. I probably won't be able to tell if there is water on the Earth, unless it rains while I am there. Are we trying to prove that if you look long enough at a single grain of sand, you can derive the whole structure of the universe?

There has to be a balance between moving on to new things and making sure you don't miss anything. If Lewis and Clarke were so focused on not missing any detail, they would have never got more than a few miles outside of St. Louis. They missed a lot of things. They knew that they had to miss them if they wanted to get the big picture.

By studying every single rock that appears interesting, you are thowing away the chance at finding great new things -- especially at this stage of the mission where the local area has already been characterized in detail.

The basic philosophy over the last 10 months has been a grave error -- a waste of 10 vital months on Mars.

The rovers have wheels for a reason. You are likely to increase the knowledge gained by orders of magnitude for every mile you drive.

In this type of exploration you must understand, acknowledge, and accept that you will miss some things. But on average, what you gain from looking at new things will vastly surpass what you miss.

Scott
.

[djellison]

Again - you're making the mistake in assuming the scientists CHOSE to stop at Purgatory and Erebus. They didn't. These are situations forced upon them by engineering limitations. There is no choice to be made. Listen to Jim Bell - they WANT to leave Erebus, they WANT to get moving, they WANT to get to Victoria JUST as much as anyone else.

To say they've learnt nothing in the last year is an horrific underestimated of what Opportunity has been up to.

"In this type of exploration you must understand, acknowledge, and accept that you will miss some things. But on average, what you gain from looking at new things will vastly surpass what you miss."

An no one knows that more than the MER team. Look at the progress they made when engineering allowed them to! 220M in a single day - that's HUGE. They barely stopped at Viking, Voyager, Vostok, Naturaliste, Argo, Arvin, Jason, James Caird, nor way back at Anatolia or Fram.....and when they did stop for science when first getting to some Erebus outcrop, they found a new previously unseen coating on the rocks adding more recent data to the story of water.

Look at Spirit, listen to Jim talk about how they totally passed up some AMAZING targets between El Dorado and Home Plate - they utterly utterly RACED that distance, these guys know how and when to give it the berries for covering ground. When they can - when it is appropriate - they do.

There is a difference between wanting to do something, and being ABLE to do something. Only the people who designed, built, and control these vehicles know their engineering limitations and know how much they can or can not do at any time. Criticism is unjustified.

Everyone, EVERYONE wants to foot-to-the-floor-to-Victoria. But just because you want something badly, doesnt make it an engineering posibility. It's that simple.


Doug